[LibreQoS] Fwd: [PATCH bpf-next v2 00/15] bpf: Support new insns from cpu v4

[LibreQoS] Fwd: [PATCH bpf-next v2 00/15] bpf: Support new insns from cpu v4

[Dave Taht]

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---------- Forwarded message ---------
From: Yonghong Song <yhs@fb.com>
Date: Wed, Jul 12, 2023, 11:07 PM
Subject: [PATCH bpf-next v2 00/15] bpf: Support new insns from cpu v4
To: <bpf@vger.kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>, Andrii Nakryiko <andrii@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>, Fangrui Song <maskray@google.com>, <
kernel-team@fb.com>


In previous discussion ([1]), it is agreed that we should introduce
cpu version 4 (llvm flag -mcpu=v4) which contains some instructions
which can simplify code, make code easier to understand, fix the
existing problem, or simply for feature completeness. More specifically,
the following new insns are proposed:
  . sign extended load
  . sign extended mov
  . bswap
  . signed div/mod
  . ja with 32-bit offset

This patch set added kernel support for insns proposed in [1] except
BPF_ST which already has full kernel support. Beside the above proposed
insns, LLVM will generate BPF_ST insn as well under -mcpu=v4 ([2]).

The patchset implements interpreter and jit support for these new
insns as well as necessary verifier support.

To test this patch set, you need to have latest llvm from 'main' branch
of llvm-project repo and apply [2] on top of it.

  [1]
https://lore.kernel.org/bpf/4bfe98be-5333-1c7e-2f6d-42486c8ec039@meta.com/
  [2] https://reviews.llvm.org/D144829

Changelogs:
  RFCv1 -> v2:
   . add more verifier supports for signed extend load and mov insns.
   . rename some insn names to be more consistent with intel practice.
   . add cpuv4 test runner for test progs.
   . add more unit and C tests.
   . add documentation.

Yonghong Song (15):
  bpf: Support new sign-extension load insns
  bpf: Fix sign-extension ctx member accesses
  bpf: Support new sign-extension mov insns
  bpf: Support new unconditional bswap instruction
  bpf: Support new signed div/mod instructions.
  bpf: Fix jit blinding with new sdiv/smov insns
  bpf: Support new 32bit offset jmp instruction
  selftests/bpf: Add a cpuv4 test runner for cpu=v4 testing
  selftests/bpf: Add unit tests for new sign-extension load insns
  selftests/bpf: Add unit tests for new sign-extension mov insns
  selftests/bpf: Add unit tests for new bswap insns
  selftests/bpf: Add unit tests for new sdiv/smod insns
  selftests/bpf: Add unit tests for new gotol insn
  selftests/bpf: Test ldsx with more complex cases
  docs/bpf: Add documentation for new instructions

 Documentation/bpf/bpf_design_QA.rst           |   5 -
 .../bpf/standardization/instruction-set.rst   | 100 ++-
 arch/x86/net/bpf_jit_comp.c                   | 131 ++-
 include/linux/filter.h                        |  14 +-
 include/uapi/linux/bpf.h                      |   1 +
 kernel/bpf/cgroup.c                           |  14 +-
 kernel/bpf/core.c                             | 174 +++-
 kernel/bpf/verifier.c                         | 315 ++++++--
 tools/include/uapi/linux/bpf.h                |   1 +
 tools/testing/selftests/bpf/.gitignore        |   2 +
 tools/testing/selftests/bpf/Makefile          |  18 +-
 .../selftests/bpf/bpf_testmod/bpf_testmod.c   |   9 +-
 .../selftests/bpf/prog_tests/test_ldsx_insn.c |  88 ++
 .../selftests/bpf/prog_tests/verifier.c       |  10 +
 .../selftests/bpf/progs/test_ldsx_insn.c      |  75 ++
 .../selftests/bpf/progs/verifier_bswap.c      |  45 ++
 .../selftests/bpf/progs/verifier_gotol.c      |  30 +
 .../selftests/bpf/progs/verifier_ldsx.c       | 115 +++
 .../selftests/bpf/progs/verifier_movsx.c      | 177 ++++
 .../selftests/bpf/progs/verifier_sdiv.c       | 763 ++++++++++++++++++
 20 files changed, 1929 insertions(+), 158 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/test_ldsx_insn.c
 create mode 100644 tools/testing/selftests/bpf/progs/test_ldsx_insn.c
 create mode 100644 tools/testing/selftests/bpf/progs/verifier_bswap.c
 create mode 100644 tools/testing/selftests/bpf/progs/verifier_gotol.c
 create mode 100644 tools/testing/selftests/bpf/progs/verifier_ldsx.c
 create mode 100644 tools/testing/selftests/bpf/progs/verifier_movsx.c
 create mode 100644 tools/testing/selftests/bpf/progs/verifier_sdiv.c

-- 
2.34.1

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